Planar separation column for use in sample analysis system

ABSTRACT

A planar separation column device for use in gas or liquid phase sample analysis. The planar separation column device includes complementary microstructures formed in a planar foldable substrate. The complementary microstructures may be superimposed in a controlled manner by folding the foldable substrate. The resulting integrated assembly may be bonded and subsequently operated in an associated sample analysis system. The planar separation column device includes etched features useful for integrated sample analysis, such as for integration of analyte inlet, detection, and fluid communication devices.

FIELD OF THE INVENTION

The present invention relates generally to miniaturized planar devicetechnology for liquid and gas phase analysis. More particularly, theinvention relates to a planar separation column for use in a sampleanalysis system.

BACKGROUND OF THE INVENTION

In sample analysis instrumentation, and especially in separation systemssuch as gas or liquid chromatography and capillary electrophoresissystems, smaller dimensions will generally result in improvedperformance characteristics and at the same time result in reducedproduction and analysis costs. In this regard, miniaturized planardevices provide more effective system design and result in loweroverhead due to decreased instrumentation sizing. Additionally,miniaturized planar devices enable increased speed of analysis,decreased sample and solvent consumption and the possibility ofincreased detection efficiency.

Several approaches towards miniaturization have developed in the art.The conventional approach provides etched planar devices on glass,silica, metal, or ceramic substrates of moderately small size. Forexample, planar devices may be etched in a wafer that receives asuperimposed cover plate. In some approaches, certain fluid handlingfunctions have not been integrated in the planar device and accordinglymust be effected by use of conventional devices, such as fused silicacapillary tubing, that are attached to the planar device. More recentapproaches have used micromachining of silicon substrates and laserablation of organic nonmetallic substrates to provide structures of muchsmaller size (i.e., microstructures) on the substrate. For example,there has been a trend towards providing planar systems having capillaryseparation microstructures. See, for example: Karasek, U.S. Pat. No.3,538,744; Terry et al., U.S. Pat. No. 4,474,889; Goedert, U.S. Pat. No.4,935,040; Sethi et al., U.S. Pat. No. 4,891,120; Shindo et al, U.S.Pat. No. 4,905,497; Miura et al., U.S. Pat. No. 5,132,012. See, also,attempts at miniaturization with respect to: gas chromatography (Widmeret al. (1984) Int. J. Environ. Anal. Chem. 18:1), high pressure liquidchromatography (Muller et al. (1991) J. High Resolut. Chromatogr.14:174; Manz et al. (1990) Sensors & Actuators B1:249; Novotny et al.,eds. (1985) Microcolumn Separations: Columns, Instrumentation andAncillary Techniques (J. Chromatogr. Library, Vol. 30); Kucera, ed.(1984) Micro-Column High Performance Liquid Chromatography, Elsevier,Amsterdam; Scott, ed. (1984) Small Bore Liquid Chromatography Columns:Their Properties and Uses, Wiley, N.Y.; Jorgenson et al. (1983) J.Chromatogr. 255:335; Knox et al. (1979) J. Chromatogr. 186:405; Tsuda etal. (1978) Anal. Chem. 50:632) and capillary electrophoresis (Manz etal. (1992) J. Chromatogr. 593:253; Manz et al. Trends Anal. Chem.10:144; Olefirowicz et al. (1990) Anal. Chem. 62:1872; Second Int'lSymp. High-Perf. Capillary Electrophoresis (1990) J. Chromatogr. 516;Ghowsi et al. (1990) Anal. Chem. 62:2714.

Micromachining techniques applied to silicon utilize a number ofestablished techniques developed by the microelectronics industryinvolving micromachining of planar materials, such as silicon.Micromachining silicon substrates to form miniaturized separationsystems generally involves a combination of film deposition,photolithography, etching and bonding techniques to fabricatethree-dimensional microstructures. Silicon provides a useful substratein this regard since it exhibits high strength and hardnesscharacteristics and can be micromachined to provide structures havingdimensions in the order of a few micrometers. Examples of the use ofmicromachining techniques to produce miniaturized separation devices onsilicon or borosilicate glass chips can be found in U.S. Pat. No.5,194,133 to Clark et al.; U.S. Pat. No. 5,132,012 to Miura et al.; inU.S. Pat. No. 4,908,112 to Pace; and in U.S. Pat. No. 4,891,120 to Sethiet al.; Fan et al., Anal. Chem. 66(1):177-184 (1994); Manz et al., Adv.Chrom. 33:1-66 (1993); Harrison et al., Sens. Actuators, B10(2): 107-116(1993); Manz et al., Trends Anal. Chem. 10 (5): 144-149 (1991); and Manzet al., Sensors and Actuators B (Chemical) B1 (1-6): 249-255 (1990).

A drawback in the silicon micromachining approach to miniaturizationinvolves the chemical activity and chemical instability of silicondioxide (SiO₂) substrates, such as silica, quartz or glass, which arecommonly used in systems for both capillary electrophoresis (CE) andchromatographic analysis systems. More particularly, silicon dioxidesubstrates are characterized as high energy surfaces and strongly adsorbmany compounds, most notably bases. The use of silicon dioxide materialsin separation systems is further restricted due to the chemicalinstability of those substrates, as the dissolution of SiO₂ materialsincreases in basic conditions (at pH greater than 7.0).

Accordingly, Kaltenbach et al., in commonly-assigned U.S. Pat. No.5,500,071, and Swedberg et al., in commonly-assigned U.S. Pat. No.5,571,410 disclose a miniaturized total analysis system comprising aminiaturized planar column device for use in a liquid phase analysissystem. The miniaturized column device is provided in a substantiallyplanar substrate, wherein the substrate is comprised of a materialselected to avoid the inherent chemical activity and pH instabilityencountered with silicon and prior silicon dioxide-based devicesubstrates. More specifically, a miniaturized planar column device isprovided by ablating component microstructures in a substrate usinglaser radiation. The miniaturized column device is described as beingformed by providing two substantially planar halves havingmicrostructures thereon, which, when the two halves are folded upon eachother, define a sample processing compartment featuring enhancedsymmetry and axial alignment.

However, although the foregoing techniques are useful in the fabricationof miniaturized planar devices for effecting fluid handling functions insample analysis systems, there are significant disadvantages to theprior art approaches. One significant problem remains in providing exactalignment of complementary pairs of microstructures that arerespectively provided in a planar substrate and its cover plate, or in apair of planar substrates, when such microstructures are intended to besuperimposed so as to subsequently be capable of performing a fluidhandling function in a unitary assembly.

For some applications, prior art planar technology has not produced asufficient degree of alignment between the superimposed microstructures.For example, and with reference to FIG. 1A, first and second substrates51, 52 are each shown to include spaced channels 53, 54 that are etchedor otherwise formed in respective surfaces 55, 56. Superposition andappropriate bonding of the surfaces 55, 56 is intended to result inexact alignment of the channels 53, 54 such that respective fluidhandling channels 61-65 are created, each of which are intended toexhibit a uniform, consistent cross-section along the major axis of thechannel. However, and as illustrated, the shortcomings of the prior artresult in channels on one substrate that are subject to variation intheir location with respect to their complementary channels on a second,complementary substrate, thus evidencing misalignment of the channelswhen the substrates are superimposed. The misalignment is sufficientsuch that the resulting conduits (such as conduits 62-64) are subject tosubstantial irregularity, and in extreme cases (such as exemplified byconduit portions 65, 66) the channels are not fully integrated.

As shown in FIG. 1B, first and second substrates 71, 72 are each shownto include spaced channels 73, 74 that are etched or otherwise formed inrespective surfaces 75, 76 by conventional techniques. Superimpositionand appropriate bonding of the surfaces 75, 76 may succeed in adequatealignment of the channels 73, 74 such that respective fluid handlingconduits 81-83 are created. However, deficiencies in many of theconventional techniques for forming the channels 73, 74 can result inedge effects and other asperities that create undesirable defects 78 inthe channels 81-83. These defects 78 retard fluid flow and createlocalized reservoirs of fluid; accordingly, the defects 78 degrade theefficiency and uniformity of fluid flowing in the channels 81-83; thedefects 78 also degrade the separation efficiency of a channel that isused to construct a separation column.

Another significant problem arises in the attempt to effect hermeticsealing of the superimposed surfaces 75, 76. This step is generallycarried out using adhesives which may not fully isolate the conduits81-83, thus resulting in cross-conduit leakage. Conventional surfacebonds may be prone to failure, leakage, or to degradation induced byadverse conditions, such as high temperature environments, or by thedestructive nature of certain gases or liquids that may be present inthe channels.

Further, silicon substrates, and most ablatable materials such aspolyimides, do not offer a sufficient combination of thermal andmechanical characteristics that otherwise would make the substrate asuseful in certain applications as the named alternative materials. Forinstance, silicon materials are not ductile and cannot be folded,shaped, etc.; ablatable materials exhibit a low coefficient of thermalconductivity and are not susceptible to rapid and uniform heating orcooling, nor do they offer sufficient strength or ductility such that anablatable substrate may be configured as a connecting member, housing,or support for other components in a sample analysis system.Furthermore, ablatable materials are expressly selected for theirpropensity to ablate upon the application of heat, and thus are notconsidered to be as robust and impervious to adverse (e.g.,high-temperature) environments in comparison to metals and metal alloys.

SUMMARY OF THE INVENTION

The present invention relates to an multilayer, integrated planar columnassembly (hereinafter, "integrated assembly") for use in a gas or liquidphase sample analysis system. The invention concerns formation ofminiaturized column devices using etching in a metallic or metal alloysubstrate.

In one aspect of the invention, an integrated assembly useful in, e.g.,sample analysis systems, may be constructed according to the inventionwherein complementary microstructures are formed by an etching orsimilar process in a planar substrate. Accordingly, the complementarymicrostructures may be superimposed in a controlled manner by operationof micro-alignment means also formed in the substrate by an etching orsimilar process. Microstructures are contemplated as including channels(that may be superimposed to form fluid conduits), apertures, conduitapertures, sample processing compartments, and the like. The resultingintegrated assembly may be operated to implement one or morefluid-handling functions.

It is a primary feature of the present invention to construct theintegrated assembly from a planar substrate having at least first andsecond component sections separated by a linear fold means, wherein saidsubstrate is comprised of a material that is ductile in the region ofthe linear fold means and substantially inextensible in the regionsdefined by the component sections. The preferred substrate material alsoexhibits appropriate thermal and mechanical characteristics such thatthe component sections of the substrate may be superimposed by foldingthe substrate at the linear fold means; then bonded and optionallyshaped to provide a unitary assembly having a useful configuration.

More specifically, it is contemplated herein to provide the integratedassembly by etching complementary microstructures in the planarsubstrate prior to folding by using conventional photolithography andetching techniques. In the preferred embodiment, an integrated assemblyis formed by providing a planar substrate having at least first andsecond adjacent component sections having a respective first and secondcomplementary microstructures etched thereon. The adjacent componentsections are separated by a linear fold means (also, preferably,provided in the substrate during the provision of the microstructures)and extend transversely from a fold axis defined by the linear foldmeans. The planar substrate is composed of a ductile material in theimmediate vicinity of the linear fold means, yet is generallyinextensible in the component sections, such that the two adjacentcomponent sections may be superimposed by folding the component sectionsupon each other about the fold axis. Upon superimposition of thecomponent sections, the first and second complementary microstructuresare precisely co-located and superimposed. The fold means constrains theco-location of the microstructures with extreme accuracy due to theinextensibility of the substrate with respect to the fold axis. Thus thecomplementary microstructures are joined with precise alignment.

In another aspect of the invention, a specialized intermediary substratemay be interposed between the mating surfaces.

In another aspect of the invention, a particularly preferred multilayerintegrated assembly includes n component sections and (n-1) linear foldmeans, wherein n equals three or more, wherein the component sectionsare closed upon one another in a Z-fold configuration upon performing afolding action along the (n-1) fold axes of said (n-1) linear foldmeans.

In another aspect of the present invention, the preferred substratematerials are especially susceptible to subsequent bonding of thecomponent sections via diffusion bonding to provide a unitary integratedassembly. A preferred diffusion bonding process in this inventioncontemplates the step of initially electroplating the surfaces to bejoined with a very thin surface layer. The integrated assembly is thenheated in vacuum to a bonding temperature above the liquidus temperatureof the nickel-base surface layer on the component sections being bonded.At this temperature the surface layer melts and a thin layer of liquidalloy wets and fills the gaps and other asperities between the twomating surfaces. The flow of the surface layer in its molten stateduring the joining operation allows the component sections to be bondedin such a way as to correct the irregularities, asperities, or otherpossible deleterious structural aspects in the mating surfaces. Inparticular, such flow will correct many of the defects that may bepresent in the interface of complementary microstructures, thusrendering the microstructures more useful.

In the practice of the invention, a preferred substrate materialcomprises a metal or metal alloy, such as steel and especially stainlesssteel. Further, the preferred substrate may be produced in long plates.A removable support means situated at the sides of the substrate may beprovided to accurately and securely transport the substrate through amanufacturing process and easily allow batch mode processing of pluralcomponent sections on a single substrate.

In a preferred embodiment of the invention, channels of a semi-circularcross section are etched by controlling the etch process. Accordingly,when a corresponding semi-circular channel is aligned with a channelthus formed, a fluid-handling structure of highly symmetrical circularcross-section is defined which may be desirable for enhanced fluid flowthrough, for example, a fluid circuit in a sample processing or sampleanalysis system.

In another aspect of the invention, an integrated assembly may Beprovided in the form of a miniaturized planar separation column deviceusing the aforementioned etching and bonding techniques applied to asuitable metal or metal alloy substrate.

It is a further related aspect of the present invention to provide asample analysis system featuring an integrated assembly for effectingfluid handling tasks, including sample injection, separation, anddetection. Further provided are means to interface the integratedassembly with a variety of external fluid handling functional devices.

ADVANTAGES OF THE INVENTION

Use of a linear fold means in a foldable substrate material to form theintegrated assembly affords several advantages over prior etching,ablation, and micromachining techniques used to form microstructures forfluid handling systems. The application of computerized control over thelithographic process allows the fold means to define, with greatprecision, a fold axis that is located equidistant from thecomplementary microstructures, thereby enabling a heightened degree ofalignment of the complementary microstructures when the assembly isintegrated by superimposing and bonding the component sections.

An intermediary substrate is contemplated as being a useful addition tothe integrated assembly so as to provide a useful characteristic thatdiffers from the characteristics in substrate used to provide thefoldable substrate. Accordingly, a intermediary substrate may beincluded to expand the functionality of the integrated assembly. Inaddition, the intermediary substrate may offer a surface treatment,structure, or function that is difficult or impractical to provide inthe substrate but which can be effectively provided in the material usedto fabricate the intermediary substrate.

In another advantage of the invention, bonding of the superimposedcomponent sections is preferably accomplished by use of a diffusionbonding technique. In a particular embodiment of the preferred diffusionbonding process, the diffusion bonding is effected utilizing a thinalloy plated layer which melts at the desired diffusion bondingtemperature, forming a transient liquid phase that is interposed in theinterface of the abutted surfaces of the component sections. Thetransient liquid phase subsequently re-solidifies at temperature as aresult of constituent interdiffusion. Continued heat treatment may beemployed to provide a homogeneous solid-state diffusion bond. The flowof the surface layer in its molten state during the joining operationallows the component sections to be be bonded in such a way as tocorrect the irregularities, asperities, or other possible deleteriousstructural aspects in the mating surfaces. In particular, such flow willcorrect many of the defects that may be present in the interface ofcomplementary microstructures, thus rendering the microstructures moreuseful.

In particular, the preferred diffusion bonding process for theintegrated assembly may be understood to include heating the assembly ina vacuum (approximately 10⁻⁵ torr) to the desired bonding temperatureabove the liquidus temperature of the nickel-base surface layer on thecomponent sections being bonded (typically in the range of 900-1000degree(s) F.) At this temperature the surface layer melts and a thinlayer of liquid alloy wets and fills the gaps and other asperities (see,for example, FIG. 1B) between the two mating surfaces. While theassembly is held at temperature, rapid diffusion of certain alloyingelements occurs between the molten alloy and the base metal, resultingin a compositional change at the joint. This change raises the localmelting point and causes the joint to isothermally solidify thuscreating the initial bond. Upon completion of the initial isothermalsolidification (typically in 1-3 hours), the joint microstructureresembles that of the base metal except for some compositional andstructural heterogeneity. Additional steps may optionally be employed incontinuation of the heat treatment at temperature for a time sufficientto completely homogenize the joint region so that, ultimately, itreaches a composition corresponding or at least closely equivalent tothe base metal, although a separate and distinct subsequent heattreatment may be utilized. After completion of the bonding process, thebonded assembly can then be given whatever further heat treatments arerequired for strengthening or in fulfillment of coating requirements.

The preferred diffusion bonding process of this invention contemplatesinitially electroplating the surfaces to be joined with a very thinnickel-base surface layer, that is, a layer of nickel,nickel-phosphorous, or a nickel-cobalt alloy.

In a particular advantage of the invention, the flow of the surfacelayer in its molten state during the joining operation allows parts ofcomplex geometry to be bonded in such a way as to correct theirregularities, asperities, or other possible deleterious structuralaspects in the mating surfaces. Such flow will correct many of thedefects that may be present in the interface of complementarymicrostructures, thus rendering the microstructure more useful.

Preferably the surface layer is composed of an alloy that is formulatedto melt at a temperature at which the base metal (in the foldablesubstrate) can be exposed without deleterious effect but must be suchthat, in terms of composition and thickness, solidification will occurat temperature, and chemical and microstructural homogeneity may beachieved in a practical processing time. Various melting pointdepressants such as phosphorous, boron, silicon, manganese, columbiumand titanium are possible. Several combinations of these elements withnickel produce surface layers with satisfactory melting points. However,as disclosed in U.S. Pat. No. 3,678,570, some depressants except boronmay produce unwanted stable phases at the joint interface.

Satisfactory bonds have been obtained between component sections in afoldable substrate formed of 316L stainless steel utilizing theforegoing process parameters and a surface layer of nickel-phosphorousalloy on the component sections. The resulting bond lines were found tobe nearly indistinguishable; more importantly, the asperities in theedges at joints between superimposed channels were filled andaccordingly indistinguishable, even after transversely sectioning theintegrated assembly and subjecting the sectioned channels to microscopicanalysis.

In another advantage of the invention, the integrated assembly will beseen to facilitate reliable connections between external fluid-handlingfunctional devices (such as fittings, valves, sensors, and the like) byuse of a single planar device for the provision of a plurality of flowpaths. The fluid-handling functional devices that connect to theintegrated assembly are preferably constructed to be surface-mounted,which has been found to offer reliable, fluid-tight connection withoutthe complexity and difficulty of conventional connections. The numberand complexity of external connections, which would otherwiseundesirably increase the volume of the flow system, are also decreased.Another advantage is that the reliability of the fluid-bearingconnections is improved.

A further advantage of the present invention is that an integratedassembly and multiple fluid-handling functional devices may becoordinated and assembled in a smaller volume than is possible in priorart systems. This results from the pneumatic channels that areintegrated in the integrated assembly, and thus many of the fluid flowpaths are integral to the integrated assembly, which is itself quitecompact and amenable to construction in a variety of shapes andconfigurations. For example, it is contemplated that the integratedassembly may be constructed in an irregular shape, such as a curved,bent, or angled configuration, so as to conform to anirregularly-shaped, compact volume.

A large number of fluid-handling functional paths may be integrated intothe integrated assembly that heretofore would be difficult if notimpossible to assemble using traditional tubular pipe, ferrules, andmanual fittings. Also, considerable cost savings and improvedreliability are realized by reduction of the number of connectionsnecessary to achieve multiple flow paths.

The surface-mounted pneumatic connections provided by the invention alsoreduce the complexity of a flow system, which is desirable during thestages of manufacturing, assembly, repair, or modification of theanalytical instrument in which the integrated assembly may be situated.

A particular advantage of the present invention is the use of processesother than silicon micromachining techniques or etching techniques tocreate microstructures in a metallic or metal alloy substrates havingdesirable attributes for an analysis portion of a sample analysissystem. The use of conventional etching processes to formmicrostructures in the preferred substrate materials, such as metalalloys, increases the ease of fabrication and lowers the per-unitmanufacturing costs in the subject devices as compared to priorapproaches, such as micromachining devices in silicon. The integratedassembly is robust (e.g., exhibits an ability to withstand adverseenvironments, mishandling, and operation at elevated temperature), iseasily cooled or heated, and is sufficiently strong and rigid so as toserve as a connecting member, support member, chassis, housing, or thelike. In this regard, devices formed according to the invention in thepreferred substrates have the added feature of being robust yet quiteinexpensive, and thus capable of use as substantially disposableminiaturized assemblies.

In another aspect of the instant invention, formation of the integratedassembly in the preferred substrate material allows for configuration ofthe integrated assembly in almost any geometry or shape. This featurenot only enables the formation of complex device configurations, butfurther allows for integration of sample preparation, sample injection,post-column reaction, and sample detection means in a miniaturizedsample analysis system having greatly reduced overall dimensions. Thecompact nature of the analysis portion in a system produced under to thepresent invention, in conjunction with the feature that integralfunctions such as injection, sample handling and detection may bespecifically engineered into the subject device to provide a sampleanalysis device, further allows for an improvement in the degree ofsystem integration, thus also accomplishing an inexpensive miniaturizedsystem.

In this regard, a miniaturized analytical system constructed accordingto the present invention is capable of performing complex samplehandling, separation, and detection methods with reduced attention by anoperator.

Provision of a modular device that includes inlet and detection meansintegrated with an integrated assembly enables enhanced on-columnanalysis or detection of components in a sample. The integrated assemblyis provided in the form of a miniaturized planar separation columndevice, and the integrated assembly has mounted thereon associatedfluid-handling functional devices, such as inlet means, valve means,detection means, and temperature control means. The resulting planarmodule is useful in a novel sample analysis system that occupies a morecompact volume as compared to sample analysis systems constructedaccording to conventional technology.

Accordingly, the subject invention finds potential application inmonitoring and/or analysis of components in chemical, biological,biochemical, pharmaceutical, and medical processes and the like.

BRIEF DESCRIPTION OF THE FIGURES

FIGS. 1A and 1B are simplified, side sectional views of a planar deviceincorporating fluid channels that is constructed in accordance with theprior art.

FIG. 2 is a cross-sectional axial view of channels formed by thealignment of complementary microstructures via closure of first andsecond component sections in a first embodiment of a foldable substrate,whereby closure provides an integrated assembly constructed according tothe present invention.

FIG. 3 is a plan view of a preferred embodiment of the foldablesubstrate of FIG. 2, prior to closure, illustrating first and secondcomplementary microstructures in respective component sections andhaving linear fold means situated between first and second componentsections,.

FIG. 4 is a pictorial representation of the foldable substrate of FIG. 3showing the linear fold means in operation during closure of thecomponent sections.

FIG. 5 is an exploded view of the foldable substrate of FIGS. 3 and 4during closure, but with the addition of a specialized intermediarysubstrate.

FIG. 6A is a pictorial representation of a first side of a secondpreferred embodiment of a foldable substrate constructed according tothe present invention and which includes a plurality of three or morecomponent sections so as to effect a Z-fold configuration.

FIG. 6B is a pictorial representation of a second side of the foldablesubstrate of FIG. 6A.

FIG. 7 is plan view of an exterior side, prior to closure, of a thirdpreferred embodiment of a foldable substrate constructed for use as aminiaturized planar fluid manifold according to the invention.

FIG. 8 is a side perspective view of the interior side of the planarfluid manifold of FIG. 7 prior to closure.

FIG. 9 is a side perspective, detailed view of a central portion of theinterior side of the planar fluid manifold of FIG. 7.

FIG. 10 is plan view of an exterior side, prior to closure, of a fourthpreferred embodiment of a foldable substrate constructed for use as aminiaturized planar separation column device constructed according tothe invention.

FIG. 11 is a plan view of the interior side, prior to closure, of theplanar separation column device of FIG. 10.

FIG. 12 is a side perspective view showing a portion of the planarseparation column device of FIG. 11.

FIG. 13 is another side perspective view showing in detail a portion ofthe planar separation column device of FIG. 11.

FIGS. 14-16 are representative separation chromatograms recorded duringthe operation of an experimental version of the embodiment of the planarseparation column illustrated in FIGS. 10-13.

FIG. 17-18 are simplified schematic diagrams of an novel sample analysisinstrument constructed according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Before the invention is described in detail, it is to be understood thatthe invention is not limited to the particular component parts of thedevices described or process steps of the methods described, as suchdevices and methods may vary. It is also to be understood that theterminology used herein is for purposes of describing particularembodiments only, and is not intended to be limiting. It must be notedthat, as used in the specification and the appended claims, the singularforms "a," "an" and "the" include plural referents unless the contextclearly dictates otherwise. Thus, for example, reference to "an analyte"includes mixtures of analytes, reference to "a detection means" includestwo or more such detection means, reference to "a sample flow component"includes more than one such component, reference to "an on-device fluidreservoir compartment" includes two or more such compartments, and thelike. In this specification and in the claims which follow, referencewill be made to a number of terms which shall be defined to have thefollowing meanings:

The use of novel construction and assembly techniques in the practice ofthe invention allows for a high degree of precision in the alignment ofsurface features other structures, which alignment has either beendifficult or not possible in prior substrate-based devices. Thus, theterm "microalignment" as used herein refers to precise alignment ofstructures, microstructures, and other surface features, including: theenhanced alignment of apertures, complementary channels, or compartmentswith each other; of inlet and/or outlet ports with channels orseparation compartments; of detection means with ports, channels orseparation compartments; and of detection means with other detectionmeans, and the like. The precision in alignment offered by the practiceof the invention is believed to be on the order of less than onemicrometer of error. In some instances, the microalignment has been soprecise that alignment error is indistinguishable even under microscopicexamination of transverse sections of bonded microstructures.

The terms "surface feature" refer to a structural feature on a componentsection that is distinguishable from the immediately surrounding portionof the component section. Examples of a surface feature include:aperture, recess, perforation, orifice, groove, chamber, compartment,depression, channel, pad, block, protrusion, nipple, and region(especially a region having a surface treatment). Note that the shape,dimensions, and symmetry of the various surface features contemplatedherein will vary according to the implementation of the invention.

"Microstructures" refers to surface features in the component sectionshaving dimensions on the order of approximately 5 to 1000 micrometersand may include microchannels, microapertures, depressions, and thelike. Microstructures in the form of microchannels of a semi-circularcross section are etched by controlling the etch process. When a firstchannel is microaligned with a second channel thus formed, afluid-handling conduit of highly symmetrical circular cross-section isdefined which may be desirable for enhanced fluid flow in, for example,a sample processing or sample analysis system. Note that the shape,dimensions, and symmetry of the various microstructures contemplatedherein will vary according to the implementation of the invention.

The terms "linear fold means" refer to means for dividing a substrateinto at least two component sections whereby the operation of the linearfold means allows microalignment of complementary surface features inthe component sections. Linear fold means can be formed in the substrateeither by etching or by other methods of fabricating shaped apertures ordepressions. Representative linear fold means that can be employedherein include a plurality of co-axially arranged apertures in componentparts and/or a plurality of corresponding features in the substrate,e.g., depressions, grooves, slots, tunnels, hollow ridges, or the like.Accurate microalignment of two or more component sections is effected byforming at least one linear fold means provided between adjacent pairsof component sections, such that each pair of the component sectionshave surfaces that can be folded to overlie each other thereby formingcomposite micro-scale features such as apertures, compartments, orchannels. Such linear fold means is preferably embodied by a row ofspaced-apart perforations etched in a particular substrate, or byspaced-apart slot-like depressions or apertures etched so as to extendonly part way through the substrate. The perforations or depressions canhave circular, diamond, hexagonal or other shapes that promote hingeformation along a predetermined straight line.

The linear fold means preferably includes a "fold relief" which refersto a relief or similar excision of the substrate that facilitatesfolding of the substrate and the subsequent microalignment of themicrostructures while maintaining the inextensibility of the substrate.The fold relief is effective at relieving the stress or deformationinduced in the substrate in the immediate area of the fold axis by thefolding motion.

The terms "foldable substrate" refer to a substrate which includeslinear fold means, at least first and second component sections sodefined by the linear fold means, and a characteristic of being foldableabout the fold axis such that the substrate material is substantiallyinextensible in the direction generally transverse to the fold axis. Asa result, the microalignment of surface features upon closure of thecomponent sections is maintained due to the lack of extension of thefoldable substrate.

The term "substantially inextensible" is used herein to refer to acharacteristic physical nature of a foldable substrate material thatresists extension from the fold axis when the foldable substrate issubject to the typical forces which it to receive during the assemblyand use of an integrated assembly. Accordingly, miniaturized columndevices are formed herein using suitable substrates which exhibitinextensibility when folded, such as metals and metal alloy substrates.

The terms "etched" and "etching" refer to surface material removalprocesses and include machining or cutting processes that providesurface features in a suitable substrate that are comparable to etchedfeatures. Etching is a preferred method for forming surface features ina wide variety of geometries. Any geometry which does not includeundercutting may be provided using etching techniques. However, otherforming methods for providing surface features are also contemplated,such as coining, fine blanking, milling, and abrading (using an abrasivein, e.g., an air or water stream.)

Etching includes such processes as common photolithography. Under thepresent invention, surface features are formed by imaging a lithographicmask onto a suitable substrate and then etching the substrate in areasthat are unprotected by the lithographic mask. Such masks may define allof the etched features for a selected area of the substrate, forexample, and the pattern may encompass multiple pairs of componentsection to be created on the substrate, each of which featurecomplementary sets of microstructures. Alternatively, individualpatterns such as an aperture pattern, a channel pattern, etc., may beplaced side by side on a common mask for stepwise exposure of largesubstrates which are eventually processed to produce a plurality ofindividual substrates. An etching system employed in the inventiongenerally includes beam delivery optics, alignment optics, a highprecision and high speed mask shuttle system, and a processing chamberincluding mechanism for handling and positioning the substrate material.

"Diffusion bonding" refers to a bonding technique which involves thesolid-state movement of the atoms and grain growth across a jointinterface. Diffusion bonding provides bonded areas which are practicallyindistinguishable from the adjacent parent metal even on closemetallurgical examination. In this regard, reference may be made to thepatent to Owczarski et al., U.S. Pat. No. 3,530,568. A particularlypreferred technique of diffusion bonding is described herein, whereinthe surfaces to be joined are initially electroplated with a very thinsurface layer (e.g., approximately 0.0003 inches or less) of nickel,nickel-phosphorous, or a nickel-cobalt alloy. The surface layer isformulated to melt at the desired diffusion bonding temperature, thusforming a transient liquid phase that fills surface defects(irregularities, asperities, and the like) at the interface of themicrostructures in the surfaces to be joined. The molten surface layersubsequently re-solidifies, thus eliminating the surface defects.

A "multilayer" integrated assembly refers to an assembly formed from afoldable substrate whereby the component sections are subject to closureso as to form at least two bonded layers. A particularly preferredmultilayer integrated assembly includes n component secions and (n-1)linear fold means, wherein n equals three or more, wherein the componentsections are closed upon one another in what is referred as a "Z-foldconfiguration" upon performing a folding action along the (n-1) foldaxes of said (n-1) linear fold means.

An "intermediary substrate" refers to an added substrate layerinterposed between the first and second component sections prior toclosure and bonding of the first and second component sections so as toprovide a composite structure. A "laminate" refers to the resultingmultilayer structure, that is, a composite structure formed using abondable intermediary substrate interposed between the first and secondcomponent sections. One particularly preferred intermediary substratecomprises an ultrathin plate, thereby providing a means for producing alaminate having layers of differing thicknesses.

The present invention will find particular application in a variety ofanalytical systems that benefit from an integrated assembly thatsupports one or more fluid handling functions with respect to one ormore fluid streams. Accordingly, the terms "fluid-handling" and"fluid-handling functions" refer to initiation, distribution,redirection, termination, control, detection, analysis, sensing,treatment, and similar functions with respect to one or more fluidstreams.

"Sample treatment" refers to sample preparation chemistries. Inparticular, an analyte of interest is generally obtained in a matrixcontaining other species which may potentially interfere with thedetection and analysis of the analyte. Accordingly, a sample treatmentcomponent is a portion of the sample processing compartment in whichanalyte separation from the matrix is effected. Examples of fluidhandling functions which may be served by the sample treatment componentinclude chromatographic separations, electrophoretic separations,electrochromatographic separations, and the like.

"Detection means" refers to means, structure or configuration which isconnectable to the integrated assembly and which allows one tointerrogate a sample using analytical detection techniques well known inthe art. Thus, a detection means may include one or more apertures,elongated apertures or grooves which are made to communicate with thesample processing compartment; alternatively, the sample detection meansmay include fittings or connections in the integrated assembly thatallows an external detection apparatus or device to be interfaced withthe sample processing compartment to detect an analyte passing throughthe compartment.

Changes in the thermal, electrical, or electrochemical properties of asample passing through the sample processing compartment can be detectedusing detection means which physically contact the sample passingthrough the sample processing compartment. In one embodiment, anelectrode may be placed within, or butt-coupled to a detection meanssuch as an aperture or a groove, thereby enabling the electrode todirectly contact the sample stream. For example, by arranging twoelectrodes (which are connected through an external conducting circuit)opposite each other relative to the sample processing compartment, anelectric field can be generated in the sample processingcompartment--transverse to the direction of sample flow--therebyproviding a ready means of electrochemical detection of analytes passingthrough the compartment. Alternatively, detectable changes in theconductivity, permittivity, or both of a particular sample due to thepresence of an analyte in the sample can be detected using anelectrometer; using a thermal conductivity detector, changes in thethermal properties of a sample passing through the sample processingcompartment can be detected.

"Analysis" refers to detecting and analyzing small and/or macromolecularsolutes in the gas or liquid phase and may employ chromatographicseparation means, electrophoretic separation means,electrochromatographic separation means, or combinations thereof. Theterms "gas phase analysis" and "liquid phase analysis" are respectivelyused to refer to analyses which are done on either small and/ormacromolecular solutes in the gas or liquid phase. Accordingly,"analysis" as used herein includes chromatographic separations,electrophoretic separations, and electrochromatographic separations.Integrated assemblies constructed according to the invention are usefulin any analysis system for detecting and analyzing small and/ormacromolecular solutes in the gas or liquid phase and may employchromatographic separation means, electrophoretic separation means,electrochromatographic separation means, or combinations thereof. Inthis regard, "chromatographic" processes generally comprise preferentialseparations of components, and include reverse-phase, hydrophobicinteraction, ion exchange, molecular sieve chromatography and likemethods.

"Fluid" refers to both to gases and liquids, and thus to all types offluids. The following description of the invention will include adescription of the arrangement, construction, or operation of certainfluid-handling devices, and hence is particularly directed to theprovision of a plurality of gaseous streams in a gas chromatographicanalytical system. However, sample analysis systems that areparticularly benefited by use of the present invention includesupercritical fluid chromatography, high-pressure gas chromatography(HPGC), liquid chromatographs, high-performance liquid chromatography(HPLC), clinical analyzers, flow-injection analyzers, laboratory waterpurification systems, syringe-type reagent dispensers, manual andautomated solid phase extraction (SPE) instruments, supercritical fluidextraction (SFE) instruments, spectrophotometers, automated protein ornucleic acid sequencers, and solid phase protein or nucleic acidsynthesizers.

"Electrophoretic" separations refers to the migration of particles ormacromolecules having a net electric charge where said migration isinfluenced by an electric field. Accordingly electrophoretic separationscontemplated for use in the invention include separations performed incolumns packed with gels (such as polyacrylamide, agarose andcombinations thereof) as well as separations performed in solution."Electrochromatographic" separation refers to combinations ofelectrophoretic and chromatographic techniques.

The term "motive force" is used to refer to any means for inducingmovement of a sample along a path in a sample analysis system, andincludes application of an electric potential across any portion of thepath, application of a pressure differential across any portion of thepath, or any combination thereof.

The term "surface treatment" is used to refer to preparation ormodification of the surface of a component section, and in particular ofa channel which will be in contact with a sample during separation,whereby the characteristics of the surface are altered or otherwiseenhanced. Accordingly, "surface treatment" as used herein includes:physical surface coatings such as silication or silane coatings;physical surface adsorptions; covalent bonding of selected moieties tofunctional groups on the surface of channel substrates; methods ofcoating surfaces, including dynamic deactivation of channel surfaces,substrate grafting to the surface of channel substrates, and thin-filmdeposition of materials such as diamond or sapphire to channelsubstrates.

"Optional" or "optionally" means that the subsequently described featureor structure may or may not be present in the embodiment or that thesubsequently described event or circumstance may or may not occur, andthat the description includes both instances where said feature orstructure is present and instances where the feature or structure isabsent, or instances where the event or circumstance occurs andinstances where it does not.

Referring generally to FIGS. 2-13, as will be appreciated by thoseworking in the field of fluid handling devices, the methods describedherein may be used to assemble a wide variety of miniaturized integratedassemblies for effecting fluid-handling functions. In the practice ofthis invention, a first component section may be arranged over a secondcomponent section and, in combination with the fold means, and byclosure of the component sections, the complementary microstructuressuperimposed therein will form, e.g., a fixed channel or compartment.According to the invention, the component sections may be sealedtogether to form a gas- or liquid-tight fluid handling functional deviceby using known pressure sealing or bonding techniques, by using externalmeans to urge the pieces together (such as clips, tension springs orassociated clamping apparatus), or by using adhesives well known in theart of bonding substrates and the like. In a particularly preferredembodiment, the component sections are hermetically sealed and bondedtogether via diffusion bonding.

It will be readily appreciated that, although a channel may berepresented in a generally extended form, channels formed according tothe invention may be etched in a large variety of configurations, suchas in a straight, serpentine, spiral, or any tortuous path desired.Further, as described in greater detail below, a channel may be formedin a wide variety of channel geometries, including semi-circular,rectangular, rhomboid, and the like, and the channels may be formed in awide range of aspect ratios. It is also noted that a device having aplurality of channels provided thereon falls within the spirit of thepresent invention.

Other particular embodiments of the invention further comprise aperturesprovided so as to communicate with a channel or compartment at a firstend thereof to form an inlet port enabling the passage of fluid from anexternal source into the channel or compartment. A second aperturecommunicates with the channel or compartment at a second end thereof toform an outlet port enabling passage of fluid from the channel orcompartment to an external receptacle. Accordingly, a miniaturizedseparation column device may be formed having a flow path extending fromthe first end of the sample processing compartment and passing to thesecond end thereof, whereby analysis of samples may be carried out usingtechniques well known in the art. An exemplary device is represented inFIGS. 10-13.

Referring now to FIG. 2, a first embodiment of an integrated assemblyfor performing one or more of a wide variety of fluid-handling functionsis formed as a miniaturized planar device 102 by providing a linear foldmeans 104 interposed between first and second component halves indicatedat 106 and 108 respectively. The support body may comprise asubstantially planar foldable substrate such as a metallic plate whichis etchable so as to enable the first and second component halves 106and 108 to each have substantially planar interior surfaces, indicatedat 110 and 112 respectively, wherein microstructures and otherminiaturized features may be etched. More particularly, a first channelpattern 114 is etched in the first planar interior surface 110 and asecond, complementary channel pattern 116 is etched in the second planarinterior surface 112. According to the invention, said first and secondchannel patterns are respectively etched in the first and secondcomponent halves 106 and 108 in locations selected according to thelocation of a fold axis defined by the linear fold means 104, such thatthe first and second channel patterns are made to be the mirror image ofeach other about the fold axis. The first and second component halves106 and 108 are then folded together and diffusion bonded to provide theplanar device 102.

Referring now to FIGS. 3-5, a second embodiment of an integratedassembly constructed according to the present invention is provided inthe form of a miniaturized planar device 150 and is formed in a foldablesubstrate 152. The integrated assembly comprises first and secondsupport body halves, indicated at 154 and 156 respectively, each havinga substantially planar interior surface indicated at 158 and 160respectively. The interior surfaces each comprise one or morecomplementary microstructures, one of which is generally indicated at162, where the complementary microstructures are arranged to provide themirror image of one another with respect to a linear fold means in amanner about to be described. Accordingly, in the practice of theinvention, the foldable substrate 152 includes means to allow the firstand second support body halves 154 and 156 to superimpose upon oneanother in a way that accurately aligns composite features defined bythe microstructures etched on said first and second planar interiorsurfaces 158 and 160.

The accurate alignment of microstructures and other surface features inthe component sections are enabled by forming such microstructures andfeatures in a foldable substrate 152 having at least one linear foldmeans, generally indicated at 180, such that a first body half 154 maybe folded onto a second body half 156. The linear fold means 180preferably includes a row of spaced-apart perforations located in thefoldable substrate 152. Alternatively, the linear fold means may includespaced-apart, slot-like depressions, grooves, or the like etched so asto extend only part way through the foldable substrate. The perforationsor depressions may have circular, diamond, hexagonal or other shapesthat promote hinge formation along a predetermined, straight line thatconstitutes the fold axis.

It is contemplated that the linear fold means allows accuratemicroalignment of features in a consistent, reliable, and simplefashion, merely by folding first body half 154 onto the second body half156. However, it is further contemplated that some applications maydemand the provision of corroboration means for corroborating thesuccessful establishment of microalignment; accordingly, either byetching or by other methods of fabricating, certain shaped features areprovided in the first body half 154 and in the second body half 156 thatare designed to physically exhibit the degree of alignment precision andare subject to inspection after closure of the foldable substrate 152.More specifically, a plurality of features 164, 170 may be provided insaid first and second support body halves 154 and 156 where saidfeatures are so arranged such that co-axial alignment thereof enablescorroboration of the precise alignment of the support body halves. Forexample, the features 164, 170 may be through-holes such that alignmentmay be corroborated using an external apparatus with means (such aslight beam) for cooperating with said co-axial apertures to observe thedegree of alignment with one another.

Hence in yet another particular embodiment of the invention,corroboration of microalignment is established by examination of thepresence of one or more blocks, one of which is formed in the first bodyhalf 154 and is indicated at 164, within a complementary window whichmay be formed in said second support body half 156, one of which isindicated at 170. Accordingly, as is readily apparent, the block 164 andwindow 170 in the corroboration means are configured to formcorresponding symmetrical or concentric structures with respect to oneanother, whereby, for example, the block 164 is easily observable by thehuman eye to be centered within the window 170 when said support bodyhalves are aligned in facing superposition with one another. In thismanner, positive and precise confirmation of the alignment of supportbody halves 154 and 156 is enabled subsequent to closure, therebyconfirming the accurate superposition of features defined by themicrostructures 162.

A wide variety of corresponding corroboration means may be formed in thesubject embodiments without departing from the spirit of the instantinvention. Such additional features include any combination of windowsand/or corresponding structures such as grooves and ridges, or, forexample, dual windows having slightly differing sizes, whereby saidfeatures cooperate to enable observation of microalignment of thecomponent sections.

With particular reference to FIG. 5, a specialized intermediarysubstrate 176 may be interposed between the body halves 154 and 156 suchthat one or more integral features, generally indicated as 178 or 179may interface with a feature or microstructure on one of the first andsecond planar interior surfaces 158 and 160. The intermediary substrate176 is contemplated as being useful for providing a characteristic thatmay differ in a useful way from the material used to provide thefoldable substrate 152. Accordingly, a intermediary substrate 176 may beincluded to expand the functionality of the planar device 150. Forexample, the intermediary substrate 176 can support a feature 178, 179of a type, structure, or function that is difficult or impractical toprovide in the foldable substrate 152 but which can be effectivelyprovided in the material used to fabricate the intermediary substrate176. Examples of such features include structural features such as: amicrostructure, conductor, semiconductor, insulator, electrode, sensor,sensor array, catalyst, orifice, screen, well, restriction, frit,perforation, porous section, or permeable or semi-permeable region.Alternatively, the feature 178, 179 may define predetermined region thatincludes a surface treatment on a particular portion of the surface ofthe intermediary substrate 176, wherein the feature includes, forexample, a surface treatment that is chemically or biologically-active;or includes a surface treatment that exhibits one or more particularlyuseful physical properties that may be difficult to provide in thefoldable substrate 52, such as an optical, electrical, opto-electrical,magneto-optical, or magnetic characteristic. In still another example,the intermediary substrate 176 can exhibit a dimensional characteristic(such as a lesser thickness) or material composition (such as a ceramicmaterial) that differs from the corresponding characteristic in thefoldable substrate, or is difficult or impractical to provide in thefoldable substrate 152.

Referring now to FIGS. 6A and 6B, a third embodiment of an integratedassembly may be provided in the form of a miniaturized planar device252', wherein n component sections are formed by definition of (n-1)linear fold means in a single foldable substrate generally indicated at288. In the illustrated embodiment, n is greater than two. The foldablesubstrate 288 thus comprises at least three component sections, e.g., afirst portion 288A, second portion 288B, third portion 288C that may beclosed upon one another according to a configuration considered hereinas a "Z-fold" configuration. The second portion 288B, having first andsecond substantially planar opposing surfaces 256' and 258',respectively, where the second portion is interposed between a firstportion 288A and a third portion 288C. The first and third portions haveat least one substantially planar surface. The first portion 288A andthe second portion 288B are separated by at least one linear fold means290 such that the first portion can be readily folded to overlie thefirst substantially planar surface 256' of the second portion 288B. Thethird portion 288C and the second portion 288B are likewise separated byat least one linear fold means 292 such that the third portion can bereadily folded to overlie the second substantially planar surface 258'of the second portion 288B. As described hereinabove, in particularlypreferred embodiments, each linear fold means 290 and 292 includes a rowof spaced-apart perforations etched in the foldable substrate, orspaced-apart slot-like depressions or apertures etched so as to extendonly part way through the foldable substrate, or the like. Theperforations or depressions can have circular, diamond, hexagonal orother shapes that promote hinge formation along a predetermined straightline.

Thus, the planar device 252' is formed by etching a first channel 260'in the first planar surface 256' of the second portion 288B, and asecond channel 262' in the second planar surface 258' of the secondportion. Each channel can be provided in a wide variety of geometries,configurations and aspect ratios. A first compartment is then formed byfolding the foldable substrate 288 at the first fold means 290 such thatthe first portion 288A covers the first channel 260' to form an elongatecompartment. A second compartment is then provided by folding thefoldable substrate 288 at the second fold means 292 such that the thirdportion 288C covers the second channel 262' to form a compartment asdescribed above. A conduit means 272', comprising an etched aperture inthe second portion 288B having an axis which is orthogonal to the firstand second planar surfaces 256' and 258', communicates a distal end ofthe first channel 260' with a first end of the second channel 262' toform a single, extended compartment.

Further, an aperture 268', etched in the first portion 288A, enablesfluid communication with the first channel 260', and a second aperture270', etched in the third portion 288C, enables fluid communication withthe second channel 262'. As described above, when the first and secondapertures are used as an inlet and outlet port, respectively, aminiaturized fluid-handling device is provided having a flow pathextending along the combined length of the first and second channels.

With reference now to FIGS. 7-13, particular embodiments of miniaturizedfluid-handling devices constructed according to the present inventionwill now be described.

As illustrated in FIGS. 7-9, a miniature planar manifold device may beprovided in a fourth embodiment of an integrated assembly formed from afoldable substrate 312; with reference to FIGS. 10-13, a miniaturizedseparation column may be provided in a fifth embodiment of an integratedassembly formed from a foldable substrate 412. In the practice of theinvention, miniaturized planar manifold device or a miniaturized planarcolumn device may be formed by etching a set of desired features in theselected foldable substrate to form complementary microstructures. Forexample, the foldable substrate 412 for a miniaturized separation columnincludes complementary microstructures having micro-capillary dimensionsranging from 50-800 micrometers in diameter and path lengths of up to 15meters or greater.

With reference to FIG. 7, the foldable substrate 312 includes first andsecond component sections 314, 316 and optional additional componentsections 318, 320. Support tabs 322A, 322B, 322C, 322D may be snappedoff of the component sections via breakable links 324 after the assemblyprocess is complete. A variety of etched microstructures arecontemplated to include: a linear fold means 330 including a lineararrangement of spaced perforations 332; device mounting holes 336; avariety of apertures 338; complementary microstructures such as channels334A and 334B; thermal breaks 340A, 340B; and microalignmentcorroboration means in the form of blocks 352 and windows 354. Thelinear fold means further includes a preferred embodiment of a foldrelief constructed in the form of a groove 362 which underlies theperforations 332. The fold relief allows the component sections 314-320to fold flat without any significant distortion of the foldablesubstrate 312 in the vicinity of the linear fold means.

The ability to exert rigid computerized control over the formation ofthe desired microstructures enables extremely precise microstructureformation, which, in turn, enables the formation of such internalfeatures as complementary micro-channels etched in two substantiallyplanar component sections, whereby those component sections may bealigned by use of the linear fold means acting in concert with the foldrelief, to define a composite sample processing compartment of enhancedsymmetry and axial alignment. In this regard, it is contemplated toprovide a further embodiment of the invention wherein etching is used tocreate two component sections which, when folded or aligned with oneanother, precisely define a miniaturized separation column device.

Accordingly, a novel miniaturized column device will be described whichis preferably etched into a substrate other than silicon or silicondioxide materials, and which avoid several major problems which havecome to be associated with prior attempts at providing micro-columndevices. The practice of the invention enables highly symmetrical andaccurately defined miniature separation column devices to be fabricatedin a wide class of metallic metal alloy substrates to provide a varietyof miniaturized sample analysis systems. In this regard, miniaturizedcolumns may be provided which have capillary dimensions (ranging from25-1500 micrometer in diameter). This feature has not been attainable inprior attempts at miniaturization, such as in capillary electrophoresis,without substantial engineering of a device after capillary formation.

A miniaturized column device may be formed in an integrated assemblyaccording to the invention by etching microstructures on component partsand aligning the components to form columns having enhanced symmetries.Formation of the subject channels in the open configuration enables awide variety of surface treatments and modifications to be applied tothe interior surfaces of the channels before formation of the sampleprocessing compartment. In this manner, a wide variety of liquid phaseanalysis techniques may be carried out in the composite sampleprocessing compartments thus formed, including chromatographic,electrophoretic, and electrochromatographic separations.

Referring now to FIGS. 10-12, a sample processing compartment may beprovided in the form of a separation column formed by superposition ofcomplementary microstructures 418A, 418B. The sample processingcompartment includes an elongate bore defined by the first and secondcomplementary channels 414 and 416. The sample processing compartmentmay be enclosed by folding the first and second component sections 406and 408 in facing abutment with each other about a fold axis defined bya linear arrangement of perforations 407. In the practice of theinvention, the first and second component halves may be held in fixablealignment with one another to form a fluid-tight sample processingcompartment using pressure sealing techniques, such as by application ofcompression force and elevated temperatures to effect diffusion bondingof the mating surfaces 411, 413.

It is further contemplated according to the invention to form first andsecond channels 414 and 416 having semi-circular cross-sections wherebyalignment of the component sections 406, 408 defines a sample processingcompartment 418 having a highly symmetrical circular cross-section toenable enhanced fluid flow therethrough; however, as discussed above, awide variety of channel geometries are also within the spirit of theinvention.

In a further preferred embodiment of the invention, it is particularlycontemplated to form the mating surfaces 411, 413 to include a surfacelayer of nickel alloy that melts at the diffusion bonding temperature soas to provide a transient liquid phase, so as to promote the filling ofsurface defects as described above.

It is further contemplated according to the invention to formcomplementary outer moat channels 411A, 413A and inner moat channels411A', 413A' that surround the outermost and innermost portions of thecompartments 418A, 418B. The first and second channels 414 and 416preferably include semi-circular cross-sections whereby alignment of thecomponent sections 406, 408 defines a sample processing compartment 418having a highly symmetrical circular cross-section to enable enhancedfluid flow therethrough. In this manner, the first and second componenthalves 406 and 408 may be diffusion bonded together without theintrusion of metal overflowing from the plated layer at the matingsurfaces 411, 413 into the channels 414 and 416. The result is a planarcapillary separation device defined by the superposition of the channels414, 416 and a liquid-tight, diffusion-bonded weld. The planar capillaryseparation device has the same thermal properties and the samemechanical strength as the bulk foldable substrate material. As aresult, the planar capillary separation device is especially susceptibleto uniform heating and cooling, which can be a benefit when effecting achromatographic sample analysis.

Referring now to FIGS. 12-13, the miniaturized column device 402 furthercomprises means for communicating associated external fluid handlingfunctional means (not shown) with the sample processing compartment 418to provide sample analysis device. More particularly, a plurality ofapertures may be etched in the foldable substrate, wherein saidapertures extend from at least one exterior surface of the support bodyand communicate with at least one channel, said apertures permitting thepassage of fluid therethrough. In this regard, an inlet port 420 may beetched in the second component half 408 and communicate with a first end422A, 422B of the first and second channel 414, 416. In the same manner,an outlet port 424 may be etched in the second component half 408 andcommunicate with a second end 426A, 426B of said first and secondchannel 414, 416.

As is readily apparent, a capillary column may thereby be formed bysuperposition of channels 414, 416, having a flow path extending fromthe first end 422A, 422B to the second end 426 thereof, by communicatingfluids from an associated source (not shown) through the inlet port 420,passing the fluids through the sample processing compartment 418 formedby the alignment of channels 414 and 416, and allowing the fluids toexit the sample processing compartment via the outlet port 424. In thismanner, a wide variety of analysis procedures may be carried out in thesubject miniaturized column device using techniques well known in theart. Furthermore, various means for applying a motive force along thelength of the sample processing compartment 418, such as a pressuredifferential or electric potential, may be readily interfaced to thecolumn device via the inlet and outlet ports, or by interfacing with thesample processing compartment via additional apertures which may beetched in the foldable substrate 404.

Inlet port 420 may be formed such that a variety of external fluidand/or sample introduction means may be readily interfaced with theminiaturized column device 402. Such means include external pressureinjection, hydrodynamic injection or electrokinetic injectionmechanisms.

The miniaturized planar column device 412 may include detection meansintegrated on the support body 404. Accordingly, a wide variety ofassociated detection means may then be interfaced to the sampleprocessing compartment 418 to detect separated analytes of interestpassing therethrough, such as by connection of electrodes to theminiaturized column at the outlet port 424.

With reference now to FIGS. 14-16, it is to be understood that while theinvention has been described in conjunction with the preferred specificembodiments thereof, that the description above as well as the examplewhich now follows are intended to illustrate and not limit the scope ofthe invention. Other aspects, advantages and modifications within thescope of the invention will be apparent to those skilled in the art towhich the invention pertains. The following examples are put forth so asto provide those of ordinary skill in the art with a complete disclosureand description of how to use the method of the invention, and is notintended to limit the scope of what the inventors regard as theirinvention. Efforts have been made to ensure accuracy with respect tonumbers (e.g., amounts, temperature, etc.) but some errors anddeviations should be accounted for. Unless indicated otherwise, partsare parts by weight, temperature is in degree(s) C. and pressure is ator near atmospheric.

EXAMPLE 1

FIG. 14 illustrates an Area Percent Report for a methane sampleseparated in a prototype planar separation column device constructedaccording to the present invention. The column included a packedstationary phase composed of 80/100 HayesSep Poraplot Q. This was 50microliter injection using a 30:1 split ratio; flow rate limited toapproximately l milliliters (ml) per minute; the temperature profile was110° C. at 1 minute with 20° C./minute ramp to 200° C. The sample was astandard methane mixture having each component at approx. 1000 PPM ofthe C1-C6 series of paraffins. The sample mixture is commerciallyavailable as Scott Mix 224 from Altech (P/N M7018). The Total Area wasdetermined to be 126109. The recorded peak results were as follows:

    ______________________________________                                               Retention                                                              Peak # Time     Area     Height                                                                              Type Width  Area %                             ______________________________________                                        1      1.234    10723    1868  BV   0.088   8.5033                            2      1.485    19937    3398  VV   0.093  15.8091                            3      2.202    25493    3263  BB   0.122  20.2148                            4      3.652    26055    2643  BB   0.151  20.6609                            5      5.130    25571    2264  BV   0.172  20.2768                            6      6.649    18330    1157  BB   0.236  14.5351                            ______________________________________                                    

EXAMPLE 2

FIG. 15 illustrates an Area Percent Report for a methane sampleseparated in a prototype planar separation column device constructedaccording to the present invention. The column was 750 micrometerdiameter, 2.5 meter length and included a packed stationary phasecomposed of 100-120 HayesSep Poraplot Q. This was 50 microliterInjection using a 30:1 split ratio; flow rate limited to approx. lmilliliters (ml) per minute; the temperature profile was 110° C. at 1minute with 20° C./minute ramp to 200° C. The sample was a standardmethane mixture having each component at approx. 1000 PPM of the C1-C5series. The Total Area was determined to be 1.1147×(10⁸). The recordedpeak results were as follows:

    ______________________________________                                              Retention                                                               Peak #                                                                              Time     Area     Type  Width Area (%)                                                                             Plates                             ______________________________________                                        1     .033     50633    BV    .033  .04542 6                                  2     .425     2912198  VH    .327  2.61249                                                                              11                                 3     .812     44175296 SHH   .087  39.62901                                                                             547                                4     1.173    38762592 ISHB  .274  34.77336                                                                             115                                5     2.122    8209008  TBV   .123  7.36418                                                                              1869                               6     2.505    181917   TVV   .149  .16320 1728                               7     2.863    349893   TVV   .426  .31388 283                                8     3.174    4640672  TVV   .133  4.16308                                                                              3577                               9     3.430    4882650  TVV   .133  4.38015                                                                              4177                               10    4.465    2749181  TVV   .183  2.46625                                                                              3739                               11    4.638    2383934  TVV   .158  2.13859                                                                              5411                               12    5.193    365206   TVV   .306  .32762 1809                               13    9.252    1809020  IVP   .438  1.62285                                                                              2802                               ______________________________________                                    

EXAMPLE 3

FIG. 16 illustrates an Area Percent Report for a methane sampleseparated in a prototype planar separation column device constructedaccording to the present invention. The column was 750 micrometerdiameter, 2.5 meter length and included a packed stationary phasecomposed of 100-120 HayesSep Poraplot Q. This was 50 microliterInjection using a 30:1 split ratio; flow rate limited to approx. lmilliliters (ml) per minute; the temperature profile was 110° C. at 1minute with 20° C./minute ramp to 200° C. The sample was a standardmethane mixture having each component at approx. 1000 PPM of the C1-C5series of paraffins. The Total Area was determined to be 1.3356×(10⁸).The recorded peak results were as follows:

    ______________________________________                                              Retention                                                               Peak #                                                                              Time     Area     Type  Width Area % Plates                             ______________________________________                                        1     .032     16344    BP    .016  .01224 25                                 2     .445     2880720  PV    .355  2.15689                                                                              10                                 3     .638     1151457  VH    .142  .86214 127                                4     .830     49386560 SHH   .098  36.97742                                                                             450                                5     .931     6215181  SHH   .090  4.65352                                                                              672                                6     1.180    36318592 SHB   .160  27.19298                                                                             342                                7     2.084    13781856 TBV   .126  10.31895                                                                             1718                               8     3.110    7795005  TPV   .132  5.83639                                                                              3486                               9     3.371    8350592  TVP   .139  6.25238                                                                              3694                               10    4.402    2991301  TPV   .122  2.23969                                                                              8176                               11    4.577    3371954  TVB   .141  2.52470                                                                              6617                               12    5.277    14784    VV    .214  .01107 3819                               13    9.239    1284390  IBP   .409  .96167 3205                               ______________________________________                                    

Turning now to FIGS. 17-18, one skilled in the art will appreciate thatbased on the foregoing description, another novel embodiment of anintegrated assembly may include sample introduction means mounted uponthe integrated assembly, or etched into the foldable substrate. In thismanner, a sample being held in an external reservoir may be introducedinto a by-pass channel to form a sample plug of a known volume; thesample plug thus formed may then be introduced into the first end of thesample processing compartment via an inlet port by communicatingexternal mechanical valving with the inlet port and apertures.

It is noted that the integrated assembly may further enable a widevariety of sample introduction techniques to be practiced according tothe invention. Particularly, having a by-pass channel which is notconnected to the sample processing compartment allows a user to flush asample through the by-pass channel without experiencing samplecarry-over or column contamination. As will be appreciated by one ofordinary skill in the art after reading this specification, one suchsample introduction technique may be effected by butt-coupling anassociated rotor to a stator (not shown) on the external surface of anintegrated assembly where the rotor selectively interfaces externaltubing and fluid sources with inlet port.

Furthermore, in the practice of the invention, external hardware may beprovided to effect the mechanical valving necessary for communication ofthe channels in an integrated assembly to different external liquidreservoirs, such as a detector gas, an electrolyte solution, flushsolution, or the sample stream delivered via apertures designed into thefoldable substrate This feature allows a variety of injection methods tobe adapted to the integrated assembly, including pressure injection,hydrodynamic injection, or electrokinetic injection.

Additionally, a variety of detection means are easily included in theintegrated assembly. In this regard, a first aperture can be etched in afirst component section, and a second aperture can likewise be formed ina second component section such that the first and second apertures willbe in co-axial alignment with internal fluid-bearing conduit when thefoldable substrate is closed. Detection of analytes in a separatedsample passing through the conduit is thereby easily enabled, such as byconnecting electrodes to the miniaturized column via apertures anddetecting using, e.g., electrochemical techniques.

Also according to the invention, a variety of means for applying amotive force along the length of the sample processing compartment maybe associated with the integrated assembly. In this regard, a pressuredifferential or electric potential may be applied along the entirelength of a sample processing compartment by interfacing motive meanswith inlet port and outlet port.

It is contemplated that external valving, detection; and injection meanscommunicate with the internal features by surface, edge, orbutt-coupling such devices to respective apertures. However, othersuitable methods of connection known in the art may easily be adapted tothe invention. Further, it is noted that numerous other sampleintroduction and fluid interfacing designs may be practiced and stillfall within the spirit of the subject invention.

Accordingly, a new and novel analytical instrument is shownschematically in FIG. 17 and is generally designated as chromatograph610. A simplified side perspective view of a planar module 620 for usein the chromatograph 610 is illustrated in FIG. 18. The planar module620 is provided in the form of an integrated assembly that includes anembodiment of the planar separation column device 412 of FIGS. 10-12 andis constructed to support and receive certain surface-mounted fluidhandling functional devices such as an inlet 612, detector 624, data andcontrol line interface 613, a temperature control means such as a planarresistive heater 616, and valves 618. Thermal breaks 642 separate atemperature-controlled zone 644 from the valve section 646.

In order to perform a chromatographic separation of a given samplecompound, a sample is injected with a pressurized carrier gas by meansof the inlet 612. The carrier gas supplied to inlet 612 is provided froma source 612A through one or more of the valves 618, each of whichserves in part to control and redirect a plurality of gas flowsincluding the carrier gas and a plurality of detector gasses ofappropriate types, such as air, hydrogen, and make-up gas. The detectorgases are provided from respective sources (one such source 624A isshown) to a valve 618. Suitable fluid-handling functional devices, suchas fittings, regulators, valves, sensors, and the like in the planarmodule 620 may be passive (such as a termination fitting) or active andhence operated under the control of the computer 622 by way of controlsignals provided on a data and control line 630 to the interface 613.For example, the pneumatic controller 626 effects control of, amongother things, fluid flow rate, fluid pressure, fluid flow regulation,and the continuity or discontinuity of flow. The control and data line630 also allows the return of sense information from appropriatesignal-interface electronics that connect to the valves 618, sensors(not shown), etc. that are provided in the planar module 620.Accordingly, the computer 622, pneumatic controller 626, and planarmodule 620 may be operated to effect a variety of fluid handlingfunctions that heretofore have been difficult to achieve in conventionalfluid-handling apparatus.

The column 614 is provided in an integrated assembly that also functionsas the supporting structure for the planar module 620. The carriergas/sample combination passing through column 614 is exposed to atemperature profile resulting in part from the operation of theresistive heater 616. During this profile of changing temperatures, thesample will separate into its components primarily due to differences inthe interaction of each component with the column 614 at a giventemperature. As the separated components exit the column 614, they aredetected by the detector 624.

Computer 622 maintains overall control of all systems associated withgas chromatograph 610. An electronic control panel 650 is shown toinclude at least two main input/output components, namely a keypad 658,and a display 660. By monitoring the operation of the chromatograph 610by signals from certain components, such as the detector 624, thecomputer 622 can initiate and maintain certain functions required for ananalytical run. Messages can be generated by computer 622 and displayedon display 660. Operating commands and other information are enteredinto computer 622 by way of keypad 658.

What is claimed is:
 1. A multilayer integrated assembly for effectingfluid handling functions for use in a sample analysis system,comprising:a planar foldable substrate having n component sections and(n-1) linear fold means defining a plurality of (n-1) fold axes, whereinn equals three or more, wherein the component sections are closed uponone another in a Z-fold configuration upon performing a folding actionalong the (n-1) fold axes of said (n-1) linear fold means, therebyhaving a first linear fold means, the first linear fold means defining alinear fold axis and first and second component sections, wherein saidfirst and second component sections include respective first and secondchannels on respective first and second mating surfaces wherein thefirst and second channels are aligned and superimposed by folding thesubstrate at the linear fold axis to form a separation column in aunitary planar assembly; inlet and outlet apertures respectivelycommunicating with inlet and outlet ends of the separation column foreffecting sample fluid flow in the separation column; and a surfacetreatment in at least one of the first and second channels; whereby themultilayer integrated assembly is useable for effecting separation ofthe sample fluid into its constituent components during said samplefluid flow.
 2. The integrated assembly of claim 1, wherein the first andsecond mating surfaces are susceptible to diffusion bonding at a desireddiffusion bonding temperature.
 3. The integrated assembly of claim 2,further comprising a surface feature on one of said first and secondcomponent sections and wherein the surface feature further includes asurface defect, and further comprising a surface layer in at least oneof the first and second mating surfaces , said surface layer beingformulated to melt at the desired diffusion bonding temperature, thusforming an amount of transient liquid phase, whereby the formation ofthe amount of the transient liquid phase altersthe surface defect. 4.The integrated assembly of claim 3, wherein the surface defect islocated at the interface of the first and second mating surfaces.
 5. Theintegrated assembly of claim 4, wherein the first and second matingsurfaces further comprise complementary microstructures.
 6. Theintegrated assembly of claim 4, wherein the first and second channelsfurther comprise complementary microstructures and further comprisingmeans for inhibiting flow of the transient liquid phase into theseparation column.
 7. The integrated assembly of claim 1, wherein thelinear fold means includes a fold relief for relieving stress ordeformation induced in the substrate in the immediate area of the foldaxis during operation of the linear fold means.
 8. The integratedassembly of claim 1, further comprising corroboration means forcorroborating the alignment of the first and second channels.
 9. Asample analysis system, comprising:an integrated assembly in the form ofa planar separation column device for use in separation of a samplepresent in a sample fluid, having a planar foldable substrate thatincludes n component sections and (n-1) linear fold means defining aplurality of (n-1) fold axes, wherein n equals three or more, andwherein the component sections are closed upon one another in a Z-foldconfiguration upon performing a folding action along the (n-1) fold axesof said (n-1) linear fold means, thereby including a first linear foldmeans defining a linear fold axis and first and second componentsections, wherein said first and second component sections includerespective first and second channels on respective first and secondmating surfaces and wherein the first and second channels are alignedand superimposed by folding the substrate at the linear fold axis toform a separation column in a unitary planar assembly, and inlet andoutlet apertures respectively communicating with the separation columnfor providing sample fluid flow in the separation column; and a surfacetreatment in at least one of the first and second channels, whereby theintegrated assembly is useable for effecting separation of the samplefluid into its constituent components during said sample fluid flow; aninlet mounted to the integrated assembly and communicating with theinlet aperture; a detector mounted to the integrated assembly andcommunicating with the outlet aperture; and motive means for effectingsample fluid flow from the inlet through the separation column to thedetector.
 10. The integrated assembly of claim 1, wherein the planarfoldable substrate further comprises a surface feature selected from thegroup consisting of: a microstructure, conductor, semiconductor,insulator, electrode, sensor, sensor array, catalyst, orifice, screen,well, restriction, frit, perforation, porous section, permeable region,and semi-permeable region.
 11. The integrated assembly of claim 1,wherein the surface treatment is selected from the group consisting of:a chemically-active region, a biologically-active region, and a regionhaving at least one optical, electrical, opto-electrical,magneto-optical, or magnetic characteristic.
 12. The integrated assemblyof claim 1, wherein said planar foldable substrate is comprised of amaterial that is ductile in the region of the linear fold means andsubstantially inextensible in the first and second component sections.13. The integrated assembly of claim 1, wherein an intermediarysubstrate is interposed between at least two of the component sections.14. The integrated assembly of claim 13, wherein the intermediarysubstrate further comprises a surface feature selected from the groupconsisting of: a microstructure, conductor, semiconductor, insulator,electrode, sensor, sensor array, catalyst, orifice, screen, well,restriction, frit, perforation, porous section, permeable region, andsemi-permeable region.
 15. The integrated assembly of claim 13, whereinthe intermediary substrate includes a surface treatment selected fromthe group consisting of: a chemically-active region, abiologically-active region, and a region having at least one optical,electrical, optoelectrical, magneto-optical, or magnetic characteristic.16. The integrated assembly of claim 13, wherein at least one of theintermediary substrate and the planar foldable substrate furthercomprises corroboration means for corroborating the alignment of theintermediary substrate and the planar foldable substrate.
 17. Theintegrated assembly of claim 2, further comprising an intermediarysubstrate interposed between at least two of the component sections ofthe planar foldable substrate and wherein the intermediary substrate andthe first and second component sections are susceptible to diffusionbonding at a desired diffusion bonding temperature.
 18. The integratedassembly of claim 1, wherein the planar foldable substrate furthercomprises a substrate material selected from the group consisting of:metal, metal alloy, steel, and stainless steel.
 19. A multilayerintegrated assembly for effecting fluid handling functions for use in asample analysis system, comprising:a planar foldable substrate having alinear fold means, the linear fold means defining a linear fold axis andfirst and second component sections, wherein said first and secondcomponent sections include respective first and second channels onrespective first and second mating surfaces, wherein the first andsecond channels are aligned and superimposed by folding the substrate atthe linear fold axis and said first and second mating surfaces aresubject to diffusion bonding at a desired diffusion bonding temperatureto form a separation column in a unitary planar assembly; and inlet andoutlet apertures respectively communicating with inlet and outlet endsof the separation column for effecting sample fluid flow in theseparation column; whereby the integrated assembly is useable foreffecting separation of the sample fluid into its constituent componentsduring said sample fluid flow.
 20. The integrated assembly of claim 19,further comprising n component sections and (n-1) linear fold meansdefining a plurality of (n-1) fold axes, wherein n equals three or more,and wherein the component sections are closed upon one another in aZ-fold configuration upon performing a folding action along the (n-1)fold axes of said (n-1) linear fold means.
 21. The integrated assemblyof claim 19, further comprising a surface feature on one of said firstand second mating surfaces and wherein the surface feature furtherincludes a surface defect, and further comprising a surface layer in atleast one of the first and second mating surfaces, said surface layerbeing formulated to melt at the desired diffusion bonding temperature,thus forming an amount of transient liquid phase, whereby the formationof the amount of the transient liquid phase alters the surface defect.22. The integrated assembly of claim 21, wherein the surface defect islocated at the interface of the first and second mating surfaces. 23.The integrated assembly of claim 21, wherein the first and secondchannels further comprise complementary microstructures, and furthercomprising means for inhibiting flow of the transient liquid phase intothe separation column.
 24. The integrated assembly of claim 19, whereinthe linear fold means includes a fold relief for relieving stress ordeformation induced in the substrate in the immediate area of the foldaxis during operation of the linear fold means.
 25. The integratedassembly of claim 19, further comprising corroboration means forcorroborating the alignment of the first and second channels.
 26. Theintegrated assembly of claim 19, wherein at least one of the first andsecond component sections further comprises a surface feature selectedfrom the group consisting of: a microstructure, conductor,semiconductor, insulator, electrode, sensor, sensor array, catalyst,orifice, screen, well, restriction, frit, perforation, porous section,permeable region, and semi-permeable region.
 27. The integrated assemblyof claim 19, wherein at least one of the first and second componentsections further comprises a surface treatment selected from the groupconsisting of: a chemically-active region, a biologically-active region,and a region having at least one optical, electrical, opto-electrical,magneto-optical, or magnetic characteristic.
 28. The integrated assemblyof claim 19, wherein said planar foldable substrate is comprised of amaterial that is ductile in the region of the linear fold means andsubstantially inextensible in the first and second component sections.29. The integrated assembly of claim 19, wherein an intermediarysubstrate is interposed between the first and second component sections.30. The integrated assembly of claim 29, wherein the intermediarysubstrate further comprises a surface feature selected from the groupconsisting of: a microstructure, conductor, semiconductor, insulator,electrode, sensor, sensor array, catalyst, orifice, screen, well,restriction, frit, perforation, porous section, permeable region, andsemi-permeable region.
 31. The integrated assembly of claim 29, whereinthe intermediary substrate includes a surface treatment selected fromthe group consisting of: a chemically-active region, abiologically-active region, and a region having at least one optical,electrical, optoelectrical, magneto-optical, or magnetic characteristic.32. The integrated assembly of claim 29, wherein at least one of theintermediary substrate and the planar foldable substrate furthercomprises corroboration means for corroborating the alignment of theintermediary substrate and the planar foldable substrate.
 33. Theintegrated assembly of claim 29, wherein the intermediary substrate andthe first and second mating surfaces are susceptible to diffusionbonding at a desired diffusion bonding temperature.
 34. The integratedassembly of claim 29, further comprising:a surface feature on at leastone of said intermediary substrate and said first and second matingsurfaces, wherein the surface feature further includes a surface defect,each of said intermediary substrate, first mating surface, and secondmating surface having a respective surface layer, said respectivesurface layers being formulated to melt at the desired diffusion bondingtemperature, thus forming an amount of transient liquid phase, wherebythe formation of the amount of the transient liquid phase alters thesurface defect.
 35. The integrated assembly of claim 19, furthercomprising:an inlet attached to the planar foldable substrate andcommunicating with the inlet aperture; a detector attached to the planarfoldable substrate and communicating with the outlet aperture; andmotive means coupled to the separation column for effecting sample fluidflow from the inlet through the separation column to the detector.